Animated sign and method of operating it



1111152, 1936- G. B. LINDERMAN, JR 2,043,200

ANIMATED lSIGN AND METHOD OF OPERATING IT I j! J5-4 .June 2, 1936. G. B. LINDERMAN. JR 2,043,200

ANIMATED SIGN AND METHOD OF OPERATING IT June 2, 1936.

ANIMATED SIGN AND METHOD OF Filed Sept. 28, 1955 G. B. LINDERMAN. JR

/23 augo'x 1 OPERATING IT 4 Sheets-Sheet 5 Ezr- 57.17

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ANIMATED SIGN AND METHOD OF OPERATING IT Filed Sept. 28, 1935 4 Sheets-Sheet 4 Patented June 2, 1936 UNITED STATES ANIMATED SIGN AND METnoD or OPERATING IT Garrett B. Linderman, Jr., Beverly, N. J., assignor to Varilux Holding Corporation,

Limited,

Nassau, Bahamas, a corporation of Bahama Islands Application September 28, 1935, Serial No. 42,683

8 Claims.

The present invention relates to animated signs` and it is particularly concerned with animated signs of the character wherein the optical eii'ect of sign indicia movement is brought about by varying the hue of light cast upon the sign, as distinguished from signs wherein the indicia itself is m'ade up of lights or luminous elements.

Signs operating on this broad principle have been heretofore proposed, but as the frequency of the light change or the rate of change of hue of the light has been of a low value, say one change per second, and as the sign indicia was primarily designed for the purpose of conveying two messages on a single sign, no real animation of sign indicia was obtained. Moreover, in such prior signs it 'was necessary that a retinal impression of the entire sign be gained during the brief space it was illuminated in order to receive the message intended to be conveyed thereby.

It is a major object of my invention to provide a novel sign wherein the indicia are of such character and are illuminated in such manner that all parts of the sign are operable to produce a continuous impression 'upon the retina of the observer, but yet in which an animated effect is produced.

It is a further important object of this invention to devise an animated sign having dual-hued indicia and which is illuminated by light oi' rapidly alternately contrasting hues, the indicia being disposed against a background which does not materially change color in response to either hue of light cast upon it, whereby the attention of the observer is concentrated upon the indicia, and a clear message conveyed.

Another object of this invention is to provide a sign adapted to be illuminated by light of rapidly contrasting hues and having indicia made up of pairs of similar shapes of contrastingly hued colors and which are of relatively small individual area, whereby a clear retinal definition of the entire sign, without conscious readjustment of the eye of the observer when the light changes in hue, is obtained.

It is a further object to provide a novel anlmated sign which is so designed as to operate upon the phenomena that the retina of the eye is more sensitive to motion than to changes in color of a body.

My invention also aims to provide r. novel animated sign which operates on a principle which for convenience will be termed the colormotion die'rential persistency principle.

Another object of my invention is to provide a novel animated sign illuminated by a light of rapidly changing hues, and having indicia. made up o1' similar shapes in pairs spaced apart on an iso-colored background, the colors of the shapes of each pair being of contrasting, preferably Il mutually exclusive hues.

My invention also aims to provide a novel animated sign adapted to be illuminated by a light of rapidly changing light of but two different hues, and yet which is adapted to convey l the impression of rotation and/or translational motion of the indicia of the sign to the eye of the observer.

Another object is to devise a novel animated sign adapted to be alternately illuminated by l light of di'erent huesv and having indicia which are designed to convey the impression of alternate expansion and contraction to the eye of the observer when the light changes in hue.

My invention also aims to provide a novel animated sign having stationary indicia which convey the impression of certain motions of the indicia to the eye of the observer when light o( rapidly changing hue is cast upon the sign, and

having a background with which the indicia cooperates to produce a coordinated animation of parts of the background and the indicia.

Further objects oi.' my invention will become apparent as the speciiication thereof proceeds in connection with the annexed drawings, and from the appended claims.

In the drawings:

' Figure 1 is a view of a sign bearing indicia designed for cooperation with a light source of alternately changing hue and adapted to be i1y 35 luminated in accordance with the method of my invention.

Figure 2 is a face view of a simple form of color hue alternator adapted to be used with the sign shown in Figure 1.

Figure 2a is a diagrammatic view in perspective illustrating one way in which the light alternator may cooperate with a light source and the various signs.

Figure 3 is a view of a sign also forming part 45 of my invention and which is somewhat similar to that of Figure l, but wherein the relationship of the positions of the colors of the indicia are reversed.

Figures 4 and 5 are views oi modified forms 5 of signs wherein the indicia produce a rocking reciprocating action, when illuminated by the apparatus of Figure 2. f

Figures 6, 7, 8 and 9 are views of modiiled signs wherein the indicia are designed to convey the impression of translational reciprocating motion when illuminated according to the method oi.' my invention.

Figures 10, 11 and 12 are views of signs also forming part of my invention and which bear indicia in the form of letters which manifest animation when illuminated according to my invention.

Figure 13 is an illustration of a further modifled form of sign'illustrating my invention as applied to a non-geometrical or pictorial representation. l

Figure 14 is a view of a sign of still further modified form and illustrates my invention as applied to a pictorial representation of more complex form, and which utilizes a combination of the effects secured in the previously illustrated forms of the invention, and

Figures 15 and 16 are plan views of modified forms of color hue alternators also forming part of my invention.

My invention comprises in its broad aspects' signs having various designs of indicia thereon and which are illuminated by light cast from a device which rapidly alternates the color or hue of the light projected upon the sign.

'Ihe sign comprises, as essential elements, indicia and a backround.

The indicia preferably take the form of geometrical forms such as circles, squares, rectangles, triangles, etc., or letters, numerals, but it also may take the form of elements of a nongeometrical pictorial representation.

The indicia is colored in flat or non-reecting hues which are preferably two in number. I have chosen to illustrate the indicia of the present embodiments of my invention as represented in the colors red and green, but it is to be understood that any other pair of contrasting and preferably mutually exclusive and preferably complementary colors may be used Without departing from the spirit of my invention.

The hues or colors of the light cast upon the sign preferably correspond substantially exactly with the hues of the indicia, and which in the present instance are red and green. In some instances a third hue may be included in the hues of light cast upon the sign. Also the sign may be additionally illuminated by constant source of light, which may or may not correspond to the hues of the indicia, depending upon the effect desired.

The rate at which the changes in the hue of light cast upon the sign take place will vary in accordance with the characteristics of the particular sign and the results desired, but I have found that the upper limit is in the neighborhood of 17 cycles per second. At this frequency the phenomena of persistence of vision produces a stationary appearance of the sign. Assuming that red or green colors are used, at the frequency of 17 cycles per second (one cycle: a change from red, green and back to red), the two colors combine to produce white light. and as the indicia respond equally to white light they accordingly appear to be motionless. The lower limit is in the neighborhood of four cycles per second, depending upon the indicia involved.

The background cooperates with the indicia in a novel manner to be hereinafter pointed out and it may take one or two colors, depending upon the nature of the sign. One color that may be assumed by the background is what I term a negative color. A negative color is one that will not respond (become visible) to either of the hues 'oi' light cast upon the sign during normal operation thereof, and the "color most frequently employed is black. The negative color accordingly will render the background substantially wholly invisible during operation of the 5 sign, and I have found this background to be particularly advantageous as it makes the indicia vividly stand out, with the result that the observers eye is not alternately attracted to the indicia and background as the light changes hue, 10 and hence the message of the sign is clearly conveyed. In some instances the sign may be constructed in an openwork fashion so that the indicia stand out in space but the background nevertheless will be of a negative color be- 15 cause it will respond to neither the red nor the green light cast upon the indicia.

The background may, for instance, when the indicia of the sign are associated with a pictorial representation, become a part of such pictorial 20 representation. If it is desired to have the picture remain constantly visible to the eye of the observer without any animation, the pictorial representation in effect becomes a background,` and in order to make it respond substantially 25 equally to each hue of light cast upon the sign, and hence appear to be motionless, it is colored in what I for convenience term a positive color or hue. What constitutes a positive color will, of cour'se, be determined by the hues of the in- 30 dicia and the light cast upon the sign. In the present embodiments of my invention I have, in the interest of brevity, shown but two hues, namely red and green, and I have found that when these colors are used in the indicia and in 35 the light cast upon the sign, yellow, brown, blue and gray shades and white constitute satisfactory positive colors.

The term hue, as applied to the signs and to the light thrown upon them, is used in its 40 broad sense; namely, a color of a certain hue may, as a matter of fact embody other hues, but the color is distinguished by the predominance of the one hue over any other hues that may be present. 45

The positive and "negative colors have one property in common because they respond equally to any hue of light cast upon the sign and hence the observers eye is attracted to the indicia of the sign. However, in the case of a 50 positive background which is constantly visible, the indicia of the sign does stand out as sharply as with a negative background, but the stationary background is nevertheless subordinated to the indicia because the latter is animated. In order to group the positive and negative background colors, I have arbitrarily termed them iso-colors.

The indicia are preferably made up of small areas or narrow lines of contrasting hues in order that a retinal image of the entire sign may be gained without causing the observer to consciously adjust his eye in an attempt to follow any individual areas of the sign as they are alternately emphasized by the hues of light cast upon them. This also avoids any tendency for the sign to manifest a flicker, which would naturally be uncomfortable to the eye and would tend to make the observer turn away from the sign.

The indicia of the sign is also designed so that when light is cast upon the sign in the manner to be hereinafter described, the figures represented will produce such a retinal impression as to be substantially continuously illuminated, and yet the figures will be highly animated. This apparently paradoxical phenomena is explained b y the fact that the retina of the eye is more sensitive to changes in the position of an object than it is to changes in the color of objects. For lnstance, assuming that we have a red area and a green area which are alternately illuminated by red and green lights at a light cycle frequency of less than 17 cycles per second. Persistence of vision. as regards color change, is effective at this frequency because-the green area appears to be constantly illuminated, (hence while red light only is cast upon the sign, and vice versa). The intensity. of the illumination varies', however, and therefore the red and green areas, though constantly'visible, are alternately emphasized, and this serves to alternately draw the attention of the observer to the red and green areas. This alternate emphasis tends to create the impression that the areas are undergoing a to and fro reciprocating motion, and as the retina of the eye is sensible of changes of position of an object below 17 cycles per second, the illusion of reciprocating is readily explained. In other words, if the color of the light cast upon the sign is changed quickly enough the retina does not have an opportunity to register the color change although it does have time to register the change in position or outline when the frequency is below 17 cycles per second, and all of the forms of my invention operate upon this principle.

'Ihe pairs of shapes making up the indicia may take the forms of pairs of concentric circles separated by areas of iso-color and preferably negative colored background. Such arrangement conveys the impression of rotation to the observer when the sign is illuminated in accordance with the present invention, whereas the indicia convey the impression of translational reciprocatory motion when the indicia assume the form of pairs disposed in generally straight or slightly curved lines, the colors alternating in the direction of the axis of the lines.

The two types of indicia just described may be combined in a single sign together with a suitably designed positive background to produce the illusion of translational movement of at least a part of the background.

The pairs of indicia just described also may be arranged in the form of closed figures such as circles, squares, rectangles or ovals, with the colors alternating in the direction of the peripheries of the figures to produce a rocking reciprocatory motion of the indica when illuminated.

The pairs of similar shapes also may take the form of letters or numbers or other designs outlined with narrow bands of red and green, the indicia exhibiting an apparent alternate enlargement and contraction as the light alternately changes from red to green and back to red.

With reference now to the drawings, wherein like reference characters are employed to designate like parts throughout the several Views thereof, I have illustrated in Figure 1 a sign I having a black background B, and indicia 2 comprising concentric circles or circular bands 3 and 4 colored red and green respectively. 'I'he background is accordingly negative, and as the background in all of the forms of my invention, with the exception of Figure 14, are negative in character, I have employed the reference character B to designate it in all of them.

'I'he pairs of bands are separated by a circular area of background B that is preferably of the same width as bands 3 and 4. When light which rapidly changes from red to green and green to red is cast V=upon the sign the bands stand out brilliantly against the black background and appear to be self-luminous. As the light changes color the bands pulsate and convey the impres- 5 sion that the circles defined by the pairs of bands alternately enlarge and contract, and also apparently rotate. When the frequency is of low magnitude, say four cycles per second, the pulsating eifect is at a maximum, and the rotating effect is 10 at a minimum. This is because at this frequency the eye has an opportunity to distinguish color changes as well as changes in the apparent position of the bands. When the frequency is higher, say sixteen cycles per second, the pulsating eil'ect 15 is somewhat subdued because the eye, at this frequency, cannot follow the color changes, whereas the rotating eiect is at a maximum at this frequency.

Throughout the range of frequencies employed 20 the bands 3 and I appear to be continuously illuminated despite the fact that the red bands are substantially totally invisible when the green light is cast upon the sign and the green bands are totallyinvisible when the red light is cast. 'I'he 25 animation which results is accordingly brought about by the emphasis which is placed upon each band as it is illuminated by the light corresponding to its color. Therefore, the animation is based on the different persistences of vision of 30 the human eye as regards motion and color change, and which I for brevity terms the colormotion differential persistency principle.

Throughout the remainder of the specification I refer to "illumination of the signs and by this 35 I mean an illumination of the sign in accordance with the method of my invention, and which will now be set forth.

In Figure 2 I have illustrated a simple form of apparatus for throwing light upon the sign and 40 it comprises a disc 5 mounted for rotation about a fixed axis and adapted to be rotated by a conn trollable speed motor. Disc 5 is provided with a pair of windows 6 and 'l of preferably equal area in which a pair of transparent screens or Win- 45 dows 8 and 9 are mounted. Windows 8 and 9 are red and green respectively and they may be made of any suitable material. If desired, windows 6 and 'l may be of unequal area so as to stress one of the colors, for instance if one of the colors 5f) is diilcult to transmit, such as blue, its windows may be made larger, in order to project blue light upon the sign for a longer time interval each cycle than the other color.

Disc 5 is adapted to be mounted between a 55 light source I0 having a condenser assembly Il (Figure 2a) for passing a concentrated beam of light through the windows, and the signs. The speed of the motor (not shown) may be controlled in any well-known manner to rotate disc 60 5 at the proper speed for the particular sign involved, and in this connection it should be observed that each revolution of the disc produces -a color cycle, as it is eifective to change the light from say green to red and back to 65 green again every time it makes a complete revolution.

Although I have shown, by way of a concrete example, a particular form of apparatus fox` illuminating the sign, it is to be understood that "0 colored light from any other suitably timed light source may be employed (with perfect satisfaction. For instance, an assembly of luminous or glow" tubes of the neon type, as shown in my co-pending application, Serial Number 672, 75

filed January 7, 1935, may be employed instead oi the present apparatus. Such glow tubes would. of course, be mounted at the margin of the sign and be concealed by a flange or the like disposed in front of the sign. In any event it is necessary to employ an apparatus capable of rapidly changing the color of the transmitted light. Electric lights of the incandescent filament type are not suitable as the filaments continue to emit lightfor a brief period after the circuit is broken, and therefore the frequencies of the present invention are not attainable therewith.

Referring to Figure 3, I have shown a sign somewhat similar to that of Figure 1, and in which circular green and red bands I2 and I3 respectively are disposed against a negative background B. The operation of this sign is similar to Figure 1 and will not be repeated other than to point out the fact that in Figure 1 the green band is the outermost band of each pair, whereas in Figure 3 the reverse is true. Accordingly, if the signs of Figures 1 and 3 are placed side-by-side in the path of the light thrown from the color alternator, the circles of one sign will appear to enlarge, while those of the other sign will simultaneously appear to contract when the light changes, and the reverse will occur when the light changes back. Therefore, these two indicia may be used together in various combinations, say as a border around a pictorial representation or the like and in many other relationships which will readily occur to those skilled in the art.

In Figure 4 I have shown a sign I4 having indicia comprising red and green areas I5 and I6 respectively which are arranged in the form of a circle. When this sign is illuminated the entire indicia will appear to rock alternately clockwise and counterclockwise, and the speed of rocking will depend upon the frequency of the light cast.

The sign I1 shown in Figure 5 is similar to that just described and comprises red and green bands or areas I8 and I9 on a black background B. In this instance bands I8 and I9 are in the forms of arrows and therefore they suggest motion. Accordingly, when sign I1 is illuminated an enhanced animated action is secured.

In connection with Figures 4 and 5, the indicia shown may be disposed one inside the other and be so colored as to produce opposite rocking e'ects when they are illuminated.

In Figures 6, 'I and 8 I have illustrated signs which produce apparent reciprocation back and forth in a straight line, as distinguished from the rocking motion of the signs of Figures 3 and 4, and with reference to Figure 6, chevronshaped red and green bands 2l and 22 are shown arranged in two rows, on sign 23 against background B, the color arrangement in the top row being opposite to that of the lower row. For instance, in the upper row the red bands are disposed to the left of the green bands, whereas in the lower row the green bands are disposed to the left of the red bands.

When sign 23 is illuminated the rows of bands will appear to reciprocate in opposite directions, and because of the shape of the bands, which suggest motion, the action is pronounced and the speed of reciprocation will depend upon the frequency of the light cast upon the sign.

In Figure 'I a similar sign 25 having red and green indicia 26 and 21 is disclosed, and in this iorm of the invention the top and bottom rows are not spaced apart. When sign 26 is illuminated it produces an effect similar to the sign of Figure 6, except that the reciprocating effect assumes a checkerboard configuration because the two rows of indicia are not spaced apart. 5

Referring to Figure 8, a sign 3I is shown having indicia comprising comparatively narrow red and green bands 32 and 33 of chevron shape against a black background B. The colors in the two rows of indicia are reversed as in the signs of lFigures 6 and 7, and the effect produced by this sign is similar to that of those signs, except that the amplitude of the reciprocation is of a lower value, because of the narrower bands and the smaller angles between them.

In Figure 9 I have shown a sign 35 having indicia composed of red and green rectangular bands 36 and 31. Although the colors. in this sign alternate in both directions, i. e., vertically and horizontally, when it is illuminated the reciprocation takes place in a vertical direction, or in a direction transverse to the major axis of each band.

The sign 39 shown in Figure 10 illustrates how letters, figures or numerals may be outlined in accordance with my invention, and in this sign the indicia is composed of two letters "M outlined n red and green bands 4I and 42 respectively against a black background B. The lefthand letter is outlined with the green band 3o on the outside, Whereas in the right-hand letter the green band is on the inside, so that when the sign is illuminated the left and right-hand letters appear to simultaneously enlarge and contract respectively during one-half of each color cycle, and to simultaneously contract and enlarge during the other half of each color cycle.

In Figures 11 and 12 I have shown signs i1- lustrating further applications of my invention to letters. In Figure 11 a sign 44 has green letters 40 which are outlined with comparatively narrow red bands 46. In Figure 12 a sign 41 illustrates several forms of the letter O. The left-hand letter is in green, and is outlined in narrow bands of red. In both of these signs a strongly anl- 45 mated effect is produced when they are illuminated because of the predominance of one color over the other. For instance, in Figure 11, and in the left-hand letters of Figure 12, green predominates, but if desired the colors may be reversed so as to allow red to predominate. Therefore, when the Alight corresponding to the color of the body of the letter is projected upon the sign the letter will appear solid, and when the other color is cast upon the sign the letter will change in character and appear in outline and will simultaneously appear to undergo an enlargement. The other two letters O shown in Figure 10 are merely outlined, and they are reversely colored so as to produce an animation similar to the sign of Figure 10 when they are illuminated.

In Figure 13 I have illustrated a sign 5I which shows my invention as applied to a pictorial representation. In this gure liquid 53 appears to flow from a bottle 54 into a tumbler 55, and they 65 preferably appear against a black background B. These parts are illustrated in positive colors; for instance, bottle 54 is brown, while liquid 53 and tumbler 55 are white. Narrow bands 56 and 61 of red and green respectively are employed to dene the edges of the stream and further bands are worked into the stream of liquid, and horizontal bands 58 and 59 of green and red are located in the tumbler. When this sign is illuminated bands 56 and 61 reciprocate laterally 75 l 2,048,200 Vor horizontally and convey the impression 'that liquid is actually flowing from the bottle linto the tumbler, and bands 58 and 58 appear as a wave or disturbance on the surface of the liquid in the tumbler. lIf desired, yellowish or brownish or other tones (positive colors) may be used to indicate the ctual color oi.' the liquid in the tumbler.

By. analyzing the action of other physicalI phenomena that may be suitable for illustration in a sign, the proper color combinations may be worked out to produce the desired animation when the sign is illuminated. 'I'he most important phase of the sign is the arrangement of the contrasting colors (in this instance red and green), and in developing the sign of Figure 13, advantage was taken of the fact that a stream of liquid flowing from a bottle or other closed receptacle alternately expands and contracts as air bubbles alternately surge into the bottle to take the place of the liquid escaping therefrom. Therefore, if the action of the phenomena which it is desired to illustrate is properly analyzed, it is apparent that the contrasting colors may be properly combined to give the desired animation.

A further sign embodying a pictorial representation 'is shown in Figure 14, and in this sign a positive background 60 is employed which is partially animated when the sign is illuminated. In this sign an ironing machine 6| having a roller 62 is shown, and a towel 63 having green borders 64 is illustrated as passing over the roller and through the machine. An operators hands 65 are shown resting on the towel. A piece of ironed material 66 is shown about to enter a basket 61, and certain lettering 68 and 69 may be employed on the sign to advertise this product and to also further suggest animation.

All of the parts just described, with the exception of the towel border and the end of the roller, are preferably colored in positive colors, and hence are visible irrespective of whether a green or red light is cast upon the sign. For instance, background 60 may be light blue, machine 6| may be executed in gray tones, roller 62 may be gray with white shading, ironed piece 66, basket 61 and the operators sleeves may be brown, and letters 68 and 69 may be yellow and white respectively. y

The animation in this sign is brought about in the following manner. Spaced red blocks 1| are located on border 64 and are preferably edged on one side in substantially negatively colored blocks 12. The end of roller 62 is made up of a positive band 13, preferably truly circular green and red bands 'I4 and 'l5 and negatively colored bands 16. Preferably red lines 11 are disposed adjacent lettering 69 and ironed piece 66. It is to be understood, however, that the arrangement of the colors just described may be reversed without departing from the spirit of my invention.

When this sign is illuminated roller 62 appears to revolve, as pointed out in connection with Figures 1 and 3, and towel1 border 64 appears to progressively move from left to right through the -machine. As pointed out in connection with Figures 4 and 5, when an arrangement of red and green blocks are disposed in straight or curved lines, as in the border of towel 63, the animation will take the form of a reciprocatory motion. However, in the present instance this action does not occur because several factors are present which bring about an illusion of forward translational movement of the towel. These factors are: (I) the association of the rotating roller with the towel, (2) the constantly visible ironing machine which conveys to the eye of the observer the suggestion that the towel should move from left to right, (3) the operators hands resting upon the towel and pointing in the direction of travel of the towel, and (l) the red lines 'I1 disposed in front of towel 63 and ironed piece 66, which alternately appear and disappear as the sign is alternately illuminated with red and green light.

It is therefore apparent that in addition to employing signs which embody indicia combining rotary and reciprocatory motions to create the illusion of progressive movement, signs may be utilized also embodying features which appeal to the mind of the observer to further the illusion of progressive translational, as distinguished from reciprocatory motion, and it is apparent that many other signs, involving different subjects, may be worked up in a similar manner utilizing my invention.

Although I have illustrated a light projector which will throw but two differently colored lights desired in some instances, depending upon the character of the signs, and the character of the animation desired, a third or fourth color of light may be cast upon the sign. As an example of one combination that may be used I have illustrated in Figure 15 a disc 5a having green, red and amber windows 8 I, 82 and 83 respectively which are preferably of equal area. When a sign is illuminated utilizing disc 5a, a light which is successively colored green, red and amber, or red, green and amber, depending upon the direction of rotation of the disc, is thrown upon the sign, and as the amber light is operative to render both the red and green areas of the sign simultaneously visible, at certain color frequencies the apparent movement of the indicia appears to be arrested when the amber light is thrown on the sign, (once, each cycle) while at other frequencies the indicia appear to continuously rotate (in the case of Figures 4 and 5) or to undergo a progressive translational movement (in the case of Figures 6, 7 and 8). It is to be understood that disc 5a may be used in illuminating all of the signs disclosed and that other colors may be used instead of, or in addition to amber.

Although I prefer to employ a sign that is illuminated solely by an intermittent light source, it is to be understood that my invention may be employed with signs which are additionally illuminated by a continuous source of light or by a further intermittent source of light which may or may not be synchronized with the source of intermittent green and red light.

In Figure 16 I have shown a further modied form of light shutter or light-hue alternator, and in this form of the invention a disc 5b is provided which is equipped with red and green windows and 86 and a blank or imperforate space 81. Windows 85 and 86 and blank space 81 are of preferably equal area.

When the various signs are illuminated using disc 5b as the light-hue alternator, an animation is secured that is somewhat different from those secured with disc 5. For instance, assuming that the sign of Figure 4 is being illuminated, if disc 5b is rotated at speeds preferably in the lower part of the range, the indicia will appear to smoothly rotate about its axis in a direction depending upon the direction of rotation of disc 5b. For instance, if the disc is rotated so as-to Aproduce the sequence red-green-blank, the indicia of Figure 4 will rotate clockwise, whereas if the sequence is green-red-blank, the rotation will be counter-clockwise.

This phenomena. is explained by the fact that the eye, in involuntarily or sub-consciously tending to follow the general movement of the light, receives the impression that the indicia is rotating. For instance, with reference to Figure 4, assuming that the light is thrown upon the sign in the sequence red-green-biank, the eye nrst registers the red areas, then the green areas and then, when the light is cut off by the blank portion of the shutter, -the eye records the blank space immediately in front of the green areas last illuminated. The eye does not tend to jump back" and register the space in back of the red areas, because the sequence is red-green-blank, and hence the eye will be attracted to the nearest blank area, and hence tend to angularly advance the position of the indicia. Therefore the eye is attracted toward the blank spaces which are disposed ahead of the red and green areas last iluminated rather than those "behind the red and green areas.

When the other signs shown in the drawings are illuminated with disc 5b other effects are produced, for instance, when the signs of Figures 6, 'I and 8 are illuminated, at certain frequencies the indicia appear to alternately advance and retract, while at other frequencies they appear to undergo a progressive translational movement depending upon the sequence used. 1f the glow tube assembly previously described is employed to illuminate the sign in this form of the invention, it is to be understood that a commutator, with suitably proportioned segments or any other suitable mechanism may be used to make and break the circuit and establish the proper time periods between the lights to produce the results just described in connection with Figure 16.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:-

1. In an animated sign, in combination, a sign presenting indicia colored in two contrasting colors, and which are deficient in the distinguishing hues of each other, said indicia comprising a plurality of elemental areas, each elemental area being substantially equally divided into two contrastingly colored parts, said elemental areas appearing against a background having a negative color and being so disposed thereon as to provide spaces between them a distance substantially equal to one-half of their width, means for causing said indicia to convey the sensation of animation to the eyes of an observer, said means comprising a device for projecting light rays of two different colors in rapid succession upon said sign, each of said light rays corresponding substantially to one of the colors of said indicia, said device being operable to alternately nood the entire sign with said light rays at speeds ranging from the speed at which all parts of said indicia tend to manifest themselves as a continuously retained retinal impression, and the speed at which perisnce of vision produces a stationary appearance of the indicia.

2. In an animated sign, in combination, a sign having a negatively colored background, and indicia disposed against said background, said s indicia comprising a series of units disposed in a line and defining a desired figure, said units each comprising an elongated narrow area disposed approximately cross-wise of the line, said units being grouped in spaced pairs, one unit of 1o' each pair being colored in one hue and the other unit of each pair being colored in another and contrasting hue, similar hues of each unit being located in the same position in each unit relatively to the hues in the other units. means for causing said indicia to convey the sensation of animation to the eye of an observer, comprising a device for projecting light of at least two different hues alternately in rapid succession upon said sign, each of said two light hues correspond- 2oA ing to one of the hues of said indicia, said device being operable to alternately nood the sign with light rays at speeds ranging from the speed at which all parts of said indicia tend to manifest themselves as continuously retained retinal im- 25.

pression, and the speed at which persistence of vision produces a stationary appearance 'of the indicia.

3. The sign described in claim 2, wherein said line is curved and assumes the form of a closed figure, and wherein said device is operable to cause said indicia to undergo an apparent angular reciprocation.

4. The sign described in claim 2, wherein said line is substantially rectilinear in form, and wherein said device is operable to cause said indicia to undergo an apparent rectilinear reciprocation.

5. The sign described in claim 2, wherein said indicia also comprises disposed adjacent to, and extending in the same general direction on said sign as the first-named series, the similar hues of the rst-named series of units being oppositely disposed with respect to the similar hues of the second-named series of 45.

units, for causing the two series of units to undergo an apparently orposite reciprocation in response to illumination by said device.

6. The method of operating a sign having indicia thereon colored in at least two contrasting hues and grouped in pairs and spaced apart on an iso-colored background, which comprises casting colored lights in rapid succession upon the sign which correspond substantially in hue to the hues of said indicia, and maintaining a time interval of transition from one hue to another which is different from that of the transition back to said one hue.

'7. The animated sign described in claim 1, to-

gether with means for projecting a third colored light upon said sign in timed relationship with said first-named colored lights and which is of a hue capable of rendering all parts of said elemental areas visible simultaneously.

8. In combination, a sign presenting indicia colored in contrasting colors which are deficient in the distinguishing hues of each other, said. indicia comprising a plurality of elemental areas, each elemental area being divided into two contrastingly colored parts, said elemental areas appearing against a. background having a negative color and being so disposed thereon as to provide spaces between them of the color of the background, means for causing said indicia to convey the sensation of animation to the eves of an oba second series of units i0` server, said means comprising a device for projecting light rays o1' two diierent colors in rapid succession upon the sign, each of said colors be- 'ing distinguished by the predominance of the hues of one of the indicia colors, said device being operable alternately to ood the sign with the light rays of different colors in rapid succession at speeds ranging from speeds atwhich the indicia manifest themselves to the eye of the observer in a condition of animation and below speed at which persistence of vision produces a stationary appearance of the indicia.

' GARREIT B. LINDERMAN, Jn. 

